How do I set the origin of an Armature
In object mode, put the 3D cursor where you want the origin to be, then select the armature and choose "set origin - origin to 3D cursor".

If you need precision for the placing, select the place (maybe a vertex, a face, a bone or whatever) and press Shift S "Cursor to selected", then again set origin.



When inspecting your file, turn off this option (that I don't even knew it existed).